In electrical-discharge-machining processes, a tool electrode is spacedly juxtaposed with a conductive workpiece across a machining gap filled with a liquid dielectric and a succession of electrical pulses are passed between the tool electrode and the workpiece to effect time-spaced electrical discharges across the machining gap, thereby electroerosively removing material from the workpiece while the tool electrode and the workpiece are relatively displaced to machine the workpiece with a desired shape. In such processes a carbonaceous body may constitute the tool electrode but a conventional carbonaceous EDM electrode has been made basically from either nongraphitized or graphitized carbon. It has been recognized that these tool electrodes suffer a considerable wear during an EDM operation and produce a relatively rough EDM machined surface on the workpiece.